slimphp Slim up to 4.15.1 HttpException::setTitle cross site scripting

Summaryinfo

A vulnerability was found in slimphp Slim up to 4.15.1. It has been rated as problematic. This issue affects the function HttpException::setTitle. The manipulation leads to cross site scripting. This vulnerability is traded as CVE-2026-48157. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in slimphp Slim up to 4.15.1. It has been rated as problematic. This issue affects the function HttpException::setTitle. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. The summary by CVE is:

Slim is a PHP micro framework that enables users to write simple web applications and APIs. In versions 4.4.0 through 4.15, if an application uses HttpException::setTitle() and/or setDescription() to include untrusted/request-derived data in the error title or description (e.g. "No products found matching '{$query}'."), an attacker could inject arbitrary HTML/JavaScript that executes in the victim's browser when they encounter an HTML error page generated by Slim. The vulnerability is present even with displayErrorDetails = false as the unescaped title and description are rendered on this error path. Built-in exceptions (HttpNotFoundException, HttpBadRequestException, etc.) ship plain-text defaults, so a vanilla Slim app with no user code is not exploitable. Only applications that feed untrusted data into setTitle() and/or setDescription() are affected. The issue has been fixed in 4.15.2. If developers are unable to immediately update their applications, they can work around this issue by avoiding passing untrusted/request-derived data into HttpException::setTitle() and setDescription() and using static, plain-text error copy instead. They should also register a custom error renderer (an ErrorRendererInterface implementation, or a subclass of HtmlErrorRenderer that escapes the title and description) for the HTML media type.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-48157 since 05/21/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 4.15.2 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Vendor

• slimphp

Name

• Slim

Version

• 4.15.0
• 4.15.1

Website

• Product: https://github.com/slimphp/Slim/

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